The University of Sheffield
Department of Molecular Biology and Biotechnology

Molecular Microbiology


Prof J Green
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Bacteria exploit virtually every environmental niche on Earth. This success depends upon their ability to adapt to a range of stresses imposed by an ever-changing environment. Understanding how bacteria respond to environmental change by exploiting their biochemical versatility is one of the most important challenges in microbial science. Research in my laboratory is focused on how bacteria respond to stress. We are particularly interested in how bacteria (Escherichia coli; Salmonella enterica; Microbacterium tuberculosis) sense and respond to changes in oxygen availability, to oxidative and nitrosative stress. These studies have led to a particular interest in characterizing signal perception, DNA recognition, and interactions with RNA polymerase for several members of the CRP-FNR family of transcription factors. In addition, we are exploiting systems approaches to learn more about the dynamics of the transcriptome as bacteria transit from one condition to another. On-going programmes are focussed on the molecular mechanisms underpinning:

  • the systems biology of E. coli catabolism
  • the action of the direct oxygen-sensor FNR 
  • the role of cyclic di-GMP signalling pathways in E. coli
  • post-transcriptional regulation by bacterial aconitase proteins
  • the role of Salmonella SlyA protein in intracellular survival
  • the action of the novel bacterial toxin haemolysin E
  • the role of CRP and Wbl proteins in Mycobacterium tuberculosis pathogenesis

 FNR

Figure legend- Oxygen sensing by the bacterial transcription factor FNR. Box on the left shows a model of a FNR monomer. Incorporation of a [4Fe-4S] cluster (Fe in red, S in yellow) promotes the formation of transcriptionally active FNR homodimers. Box on the right shows the reaction of the FNR [4Fe-4S] cluster with oxygen to yield the transcriptionally inactive [2Fe-2S] form of the protein.

 

Selected recent publications

Rolfe, M.D., Ter Beek, A., Graham, A.I., Trotter, E. W., Asif, H.M.S., Sanguinetti, G., Teixeira de Mattos, J., Poole, R.K. and Green, J. (2011) Transcript profiling and inference of Escherichia coli K-12 ArcA activity across the range of physiologically relevant oxygen concentrations. Journal of Biological Chemistry in press

Crack, J.C., Smith, L.J., Stapleton, M.R., Peck, J., Watmough, N.J., Buttner, M.J., Buxton, R.S., Green, J., Oganesyan, V.S., Thomson, A.J. and Le Brun, N.E. (2011) Mechanistic insight into the nitrosylation of the [4Fe-4S] cluster of WhiB-like proteins. Journal of the American Chemical Society 133, 1112-1121

Smith, L.J., Stapleton, M.R., Fullstone, G.J.M., Crack, J.C., Thomson, A.J., Le Brun, N.E., Hunt, D.M., Harvey, E., Adinolfi, S., Buxton, R. S. and Green, J. (2010) Mycobacterium tuberculosis WhiB1 is an essential DNA-binding protein with a nitric oxide sensitive iron-sulfur cluster. Biochemical Journal 432, 417-427

Lacey, M.M., Partridge, J.D. and Green, J. (2010) Escherichia coli YfgF is an anaerobic cyclic di-GMP phosphodiesterase with roles in cell surface remodelling and the oxidative stress response. Microbiology 165, 2873-2886.

Stapleton, M.R., Haq, I., Hunt, D.M., Arnvig, K.B., Artymiuk, P.J., Buxton, R.S. and Green, J. (2010) Mycobacterium tuberculosis cAMP receptor protein (Rv3676) differs from the Escherichia coli paradigm in its cAMP binding and DNA binding properties and transcription activation properties. Journal of Biological Chemistry 285, 7016-7027.

Jervis, A.J., Crack, J.C., White, G., Artymiuk, P.J., Cheesman, M.R., Thomson, A.J., Le Brun, N., and Green, J. (2009) The O2 sensitivity of the transcription factor FNR is controlled by Ser24 modulating the kinetics of the [4Fe-4S] to [2Fe-2S] cluster conversion. Proceedings of the National Academy of Sciences USA 106, 4659-4664.

Selected earlier publications

Ryan, R.M., Green, J., Hunt, S., Williams, P.J., Tazzyman, S., Harmey, J.H., Kehoe, S.C. and Lewis, C.E. (2009) Bacterial delivery of a novel cytolysin to hypoxic areas of solid tumors. Gene Therapy 16, 329-339

Lithgow, J.K., Haider, F., Roberts, R.E. and Green, J. (2007) Alternate SlyA and H-NS nucleoprotein complexes control hlyE expression in Escherichia coli K-12. Molecular Microbiology 66, 685-698

Partridge, J.D., Sanguinetti, G., Dibden, D.P., Roberts, R.E., Poole, R. K. and Green, J. (2007) Transition of Escherichia coli from aerobic to anaerobic conditions involves fast and slow reacting regulatory components. Journal of Biological Chemistry 282, 11230-11237

Crack, J., Green, J., Cheesman, M., Le Brun, N. E. and Thomson, A. J. (2007) Superoxide-mediated amplification of the oxygen-induced switch from [4Fe-4S] to [2Fe-2S] clusters in the transcriptional regulator FNR. Proceedings of the National Academy of Sciences USA 104, 2092-2097

Rickman, L., Scott, C., Hunt, D.M., Hutchinson, T., Menendez, M.C., Whalan, R., Hinds, J., Colston, M.J., Green, J. and Buxton, R.S. A member of the cAMP receptor protein family of transcription regulators in Mycobacterium tuberculosis is required for virulence in mice and controls transcription of the rpfA gene encoding for a resuscitation promoting factor. Molecular Microbiology 56, 1274-1286

Tang, Y., Guest, J.R., Artymiuk, P.J. and Green, J. (2005) Switching aconitase between catalytic and regulatory modes involves iron-dependent dimer formation. Molecular Microbiology 56, 1149-1158

Wallace, A., Stillman, T.J., Atkins, A., Jamieson, S.J., Bullough, P.A., Green, J., and Artymiuk, P.J. (2000) E. coli hemolysin E (HlyE, ClyA, SheA): X-ray crystal structure of the toxin and observation of membrane pores by electron microscopy. Cell 100, 265-276